Chronic bronchitis is one of the obstructive airway disorders, commonly seen in smokers.
Chronic bronchitis is defined clinically as persistent cough with sputum production for at least 3 months in at least 2 consecutive years, in the absence of any other identifiable cause.
Types:
Simple chronic bronchitis(not associated with any other obstructive disorder)
Asthmatic bronchitis (with hyperreactive airways)
Obstructive chronic bronchitis (with emphysema)
Etiopathogenesis
Smoking is the most important etiology. About 90% of patients with chronic bronchitis are smokers. The pathogenesis is explained in the illustration below
Microscopy
Chronic inflammation is seen in the walls of airways.
There is enlargement and increase in the number of the mucus-secreting glands.
Assessed by the ratio of the thickness of the mucous gland layer to the thickness of the wall between the epithelium and the cartilage (Reid index).
The normal REID index is 0.4
The REID index is increased in chronic bronchitis and is proportional to the severity and duration of the disease.
Clinical features
Persistent cough with sputum.
Dyspnea on exertion develops in later course of the disease.
Long-standing severe chronic bronchitis leads to Cor-pulmonale with cardiac failure.
